In recent years, new transportation systems have attracted attention as new transportation means other than buses and railways. As one type of such new transportation systems, a type which allows a vehicle having traveling wheels formed of rubber tires to travel on tracks is known.
The tracks on which this type of vehicle travels are configured to have concrete travel paths on which the traveling wheels roll, and guide rails as guide tracks provided along the travel paths. The vehicle has guide wheels in addition to the traveling wheels, and a traveling direction is restricted by bringing the guide wheels into contact with the guide rails provided along the travel paths.
As one of factors for improving the ride quality of this type of vehicle, there is flatness of the travel paths. As a method for enhancing the flatness of the concrete surface, for example, as described in the following Patent Document 1, there is a method of grinding the surface of the concrete after curing using a grinding device. This grinding device includes grinders, a frame on which the grinders are provided, and a vacuum pad which holds the frame on the surface to be machined by suctioning a surface to be machined. This device is used for grinding an installation floor surface for a device which requires installation accuracy, such as a high precision machining device or an analytical device.